Arm

Question 1

Give Origin, Insertion, Innervation and Action of:

Biceps Brachii

Answer 1

Origin:
Long head = Supraglenoid tubercle of scapula
Short head = Coracoid process of scapula

Insertion:
Tuberosity of the radius and fascia of the forearm (via Bicipital aponeurosis)

Innervation:
Musculocutaneous (C5,6,7)

Action:

• Main supinator of the forearm
• When supine, flexes forearm
• Short head helps resist dislocation of shoulder

Question 2

Give Origin, Insertion, Innervation and Action of:

Brachialis

Answer 2

Origin:
Anterior side of distal half of humerus

Insertion:
Coronoid process of ulna
Tuberosity of the ulna

Innervation:
Musculocutaneous nerve (C5,6,7)

Action:
Flexion of the forearm

Question 3

Name the muscles in the anterior arm

Answer 3

Biceps Brachii
Brachialis
Coracobrachialis

Question 4

Give Origin, Insertion, Innervation and Action of:

Coracobrachialis

Answer 4

Origin:
Coracoid process

Insertion:
Middle third of medial humerus

Innervation:
Musculocutaneous Nerve (C5,6,7)

Action:
Flexion of the arm
Help with Adduction of arm
Prevent dislocation of the shoulder

Question 5

Name the muscle in the posterior arm

Answer 5

Triceps Brachii

Question 6

Give Origin, Insertion, Innervation and Action of:

Triceps Brachii

Answer 6

Origin:
Long head: Infaglenoid tubercle of the scapula
Medial head: Posterior humerus (inferior to radial groove)
Lateral head: Posterior humerus (superior to radial groove)

Insertion:
Proximal Olecranon process + fascia of forearm

Innervation:
Radial Nerve (C5,6,7,8,T1)

Action:
Extension of forearm
Long head helps resist shoulder dislocation
Long head helps adduct arm